ISSN:
0449-2951
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Because of their commercial importance, the reaction sequences and structures of resins produced when phenol reacts with formaldehyde have been studied by numerous different chemical and physical methods. Many details concerning these reactions and complex chemical structures are still not entirely understood. Most of the experimental methods used have yielded only qualitative information. Many of these methods have been applicable only to the lower molecular weight portions of soluble prepolymers. The present work describes proton magnetic resonance (PMR) methods which yield detailed and quantitative number-average structures for any soluble phenol-formaldehyde resin. It is shown that benzyl-type hemiformals make substantial contributions to the structures of many resoles and that these functionalities exhibit relatively high stability under certain conditions of initial cure. The structures of several resins are discussed in terms of certain aspects of reactions which occurred during the resin syntheses. These reactions include hydroxymethylations and condensations yielding diphenylmethane-type and dibenzyl ether-type bridges. To define the mechanisms and rates of the various reactions at different temperatures and under different catalytic conditions, a much more detailed study is required. Potentially, the PMR methods described can provide most of the necessary quantitative data.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1965.100030320
Permalink
